Blood pressure readings are given in two numbers. The top number is the maximum pressure your heart exerts while beating (systolic pressure), and the bottom number is the amount of pressure in your arteries between beats (diastolic pressure).

The numeric difference between your systolic and diastolic blood pressure is called your pulse pressure. For example, if your resting blood pressure is 120/80 millimeters of mercury (mm Hg), your pulse pressure is 40.

For adults older than age 60, a pulse pressure greater than 60 can be a useful predictor of heart attacks or other cardiovascular disease; this is especially true for men.

In some cases a low pulse pressure (less than 40) may indicate poor heart function. A higher pulse pressure (greater than 60) may reflect leaky heart valves (valve regurgitation), often due to age-related losses in aortic elasticity.

However, systolic and diastolic pressure should also be considered alongside pulse pressure values. Higher systolic and diastolic pairs imply higher risk than lower pairs with the same pulse pressure: 160/120 millimeters of mercury (mm Hg) indicates a higher risk than 110/70 mm Hg even though the pulse pressure in each pair is 40.

The most important cause of elevated pulse pressure is stiffness of the aorta, the largest artery in the body. The stiffness may be due to high blood pressure or fatty deposits damaging the walls of the arteries, leaving them less elastic (atherosclerosis). The greater your pulse pressure, the stiffer and more damaged the vessels are thought to be.

Other conditions — including severe iron deficiency (anemia) and an overactive thyroid (hyperthyroidism) — can increase pulse pressure as well.

Treating high blood pressure often reduces pulse pressure, although different medications may have varying impacts.

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Aug. 02, 2016 See more Expert Answers